After the Le Chi Vien massacre, only a five-year-old boy, grandchild of Nguyen Trai, in Nguyen Trai Family survives. A family servant takes the boy to run away from the hunt of the Queen Mother Tuyen Tu Hoang. King Le Nhan Tong is enthroned at age of 2, so the Queen Mother Tuyen Tu Hong takes control on everything in the royal palace. 12 years later, the survived boy now becomes a sturdy, smart and talent guy with a new name of Tran Nguyen Vu. After being unveiled the truth of his biography and the family’s tragic secret, Nguyen Vu gets down the mountain and starts a dangerous journey. He mingles into the royal palace to take the revenge on the enemies who killed his family to readdress for his family. In the palace, Nguyen Vu discovers more clandestine and conspiracies between royal arms and parties. However, the rumor about the existence of a blood letter behind the Le Chi Vien massacre makes them hesitate for any moves. In that inimical space, Nguyen Vu meets Hoa Xuan, a beautiful girl who also has the same animosity and is seeking way to revenge. The fate takes them together to hunt for the blood letter. They have to battle with deadly schemes, barbarous massacres and confrontation between murderers and knights. However, when having the blood letter, Nguyen Vu recognizes that the peace of innocent residents is more important than justice for his family. Finally, Nguyen Vu decides to cash off animosity.